Class: PgPipeline::Pool

Inherits:
Object
  • Object
show all
Defined in:
lib/pg_pipeline/pool.rb

Constant Summary collapse

DEFAULT_PIPELINE_SIZE = 
4
DEFAULT_PINNED_SIZE = 
2
DEFAULT_RECONNECT_INTERVAL = 
0.5
DEFAULT_RECONNECT_BACKOFF_MAX = 
30.0
DEFAULT_HEALTH_INTERVAL = 
10.0
DEFAULT_HEALTH_TIMEOUT = 
5.0
DISCARD_SEQUENCES_SERVER_VERSION = 
90_400
CANCEL_SIGNAL = 
Async::Cancel

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(connection_args, pipeline_size: DEFAULT_PIPELINE_SIZE, pinned_size: DEFAULT_PINNED_SIZE, max_pending: ConnectionDriver::DEFAULT_MAX_PENDING, max_in_flight: ConnectionDriver::DEFAULT_MAX_IN_FLIGHT, reconnect: true, reconnect_interval: DEFAULT_RECONNECT_INTERVAL, reconnect_backoff_max: DEFAULT_RECONNECT_BACKOFF_MAX, health_check: true, health_interval: DEFAULT_HEALTH_INTERVAL, health_timeout: DEFAULT_HEALTH_TIMEOUT, cancel_pinned_on_abort: true) ⇒ Pool

Returns a new instance of Pool.



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# File 'lib/pg_pipeline/pool.rb', line 26

def initialize(connection_args,
               pipeline_size: DEFAULT_PIPELINE_SIZE,
               pinned_size: DEFAULT_PINNED_SIZE,
               max_pending: ConnectionDriver::DEFAULT_MAX_PENDING,
               max_in_flight: ConnectionDriver::DEFAULT_MAX_IN_FLIGHT,
               reconnect: true,
               reconnect_interval: DEFAULT_RECONNECT_INTERVAL,
               reconnect_backoff_max: DEFAULT_RECONNECT_BACKOFF_MAX,
               health_check: true,
               health_interval: DEFAULT_HEALTH_INTERVAL,
               health_timeout: DEFAULT_HEALTH_TIMEOUT,
               cancel_pinned_on_abort: true)
  @connection_args = connection_args
  @pipeline_size = PoolOps.positive_integer!(pipeline_size, :pipeline_size)
  @pinned_size = PoolOps.nonnegative_integer!(pinned_size, :pinned_size)
  @max_pending = max_pending
  @max_in_flight = max_in_flight
  @reconnect = reconnect
  @reconnect_interval = PoolOps.finite_float!(reconnect_interval, :reconnect_interval)
  @reconnect_backoff_max = PoolOps.finite_float!(reconnect_backoff_max, :reconnect_backoff_max)
  @health_check = health_check
  @health_interval = PoolOps.finite_float!(health_interval, :health_interval, allow_zero: true)
  @health_timeout = PoolOps.finite_float!(health_timeout, :health_timeout)
  @cancel_pinned_on_abort = cancel_pinned_on_abort

  @drivers = []
  @driver_backoff = []
  @driver_attempts = []
  @driver_last_health = []
  @rr = 0
  @rr_slot = [0]
  @reconnects = 0
  @health_failures = 0
  @supervisor_error = nil
  @supervisor = nil
  @task_parent = nil

  @prepared_statements = {}
  @prepared_generation = 0
  @statement_sequence = 0

  @pinned_free = []
  @pinned_in_use = {}
  @pinned_gate = nil
  @pinned_error = nil
  @pinned_active = 0
  @pinned_owners = Hash.new(0)
  @pinned_idle = Async::Notification.new

  @started = false
  @closing = false
  @closed = false
end

Instance Attribute Details

#pipeline_size ⇒ Object (readonly)

Returns the value of attribute pipeline_size.



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# File 'lib/pg_pipeline/pool.rb', line 24

def pipeline_size
  @pipeline_size
end

#reconnects ⇒ Object (readonly)

Returns the value of attribute reconnects.



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# File 'lib/pg_pipeline/pool.rb', line 24

def reconnects
  @reconnects
end

Instance Method Details

#abort! ⇒ Object 



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# File 'lib/pg_pipeline/pool.rb', line 259

def abort!
  return unless @started || @closing

  @closing = true
  @started = false
  first_error = nil

  begin
    first_error = preferred_shutdown_error(first_error, stop_supervisor)
    if @cancel_pinned_on_abort
      first_error = preferred_shutdown_error(first_error, cancel_in_use_pinned)
    end
    first_error = preferred_shutdown_error(first_error, close_all_drivers(:abort!))
  ensure
    close_free_pinned
    @closed = true
  end

  raise first_error if first_error

  nil
end

#closing? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pg_pipeline/pool.rb', line 105

def closing? = @closing

#graceful_close ⇒ Object 



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# File 'lib/pg_pipeline/pool.rb', line 229

def graceful_close
  return unless @started

  if @pinned_owners[Async::Task.current].positive?
    raise Error, "cannot close the pool from inside Client#session/transaction"
  end

  @closing = true
  @started = false
  first_error = nil

  begin
    first_error = preferred_shutdown_error(first_error, stop_supervisor)
    first_error = preferred_shutdown_error(first_error, close_all_drivers(:graceful_close))

    begin
      wait_for_pinned_idle
    rescue CANCEL_SIGNAL, StandardError => e
      first_error = preferred_shutdown_error(first_error, e)
    end
  ensure
    close_free_pinned
    @closed = true
  end

  raise first_error if first_error

  nil
end

#pipeline_driver ⇒ Object

Raises:



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# File 'lib/pg_pipeline/pool.rb', line 107

def pipeline_driver
  ensure_available!

  driver = PoolOps.select_driver_into(@drivers, @rr, @rr_slot)
  @rr = @rr_slot[0]
  raise NotDispatchedError, "no live pipeline connections; request was not dispatched" unless driver

  driver
end

#prepare_statement(client, name, sql, param_types) ⇒ Object 



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# File 'lib/pg_pipeline/pool.rb', line 117

def prepare_statement(client, name, sql, param_types)
  ensure_available!
  logical_name = PreparedStatementOps.snapshot_name(name)
  if @prepared_statements.key?(logical_name)
    raise Error, "prepared statement #{logical_name.inspect} already exists"
  end

  @statement_sequence += 1
  statement = PreparedStatement.new(
    client: client,
    name: logical_name,
    physical_name: "pgp_#{@statement_sequence.to_s(36)}",
    sql: sql,
    param_types: param_types
  )

  @prepared_statements[logical_name] = statement
  @prepared_generation += 1
  requests = []

  begin
    drivers = @drivers.select(&:available?)
    if drivers.empty?
      raise NotDispatchedError, "no live pipeline connections; statement was not prepared"
    end

    requests = drivers.map do |driver|
      Request.prepare(statement).tap { |request| driver.submit(request) }
    end

    first_error = nil
    requests.each do |request|
      begin
        RequestOps.clear_result(request.wait)
      rescue StandardError => e
        if first_error
          e.clear_result! if e.respond_to?(:clear_result!)
        else
          first_error = e
        end
      end
    end
    raise first_error if first_error

    statement
  rescue Exception
    if @prepared_statements.delete(logical_name)
      @prepared_generation += 1
    end
    raise
  ensure
    requests.each { |request| request.cancel! unless request.settled? }
  end
end

#start(parent: nil) ⇒ Object

Raises:



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# File 'lib/pg_pipeline/pool.rb', line 80

def start(parent: nil)
  raise Error, "pool already started" if @started
  if @closing || @closed
    raise ShutdownError, "pool is closing or was closed and cannot be restarted; create a new Pool"
  end

  parent ||= Async::Task.current
  @task_parent = parent

  begin
    @pipeline_size.times { @drivers << start_pipeline_driver(parent) }
    @driver_backoff = Array.new(@drivers.size, 0.0)
    @driver_attempts = Array.new(@drivers.size, 0)
    @driver_last_health = Array.new(@drivers.size, monotonic)
    @pinned_gate = Async::Semaphore.new(@pinned_size) if @pinned_size.positive?
    @started = true
    @supervisor = parent.async { supervise } if @reconnect || @health_check
  rescue Exception
    cleanup_partial_start
    raise
  end

  self
end

#stats ⇒ Object 



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# File 'lib/pg_pipeline/pool.rb', line 206

def stats
  {
    pipeline: {
      size: @pipeline_size,
      live: @drivers.count(&:available?),
      drivers: @drivers.map(&:stats)
    },
    pinned: {
      size: @pinned_size,
      active: @pinned_active,
      free: @pinned_free.size,
      in_use: @pinned_in_use.size
    },
    prepared_statements: (@prepared_statements || {}).size,
    reconnects: @reconnects,
    health_failures: @health_failures,
    supervisor_error: @supervisor_error&.message,
    closing: @closing,
    closed: @closed,
    pinned_error: @pinned_error&.message
  }
end

#with_pinned ⇒ Object

Raises:

  • (@pinned_error) 


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# File 'lib/pg_pipeline/pool.rb', line 172

def with_pinned
  ensure_available!
  raise @pinned_error if @pinned_error
  raise Error, "pinned pool is disabled (pinned_size=0)" if @pinned_size.zero?

  if @pinned_owners[Async::Task.current].positive?
    raise RecursiveCheckoutError,
          "nested Client#session/transaction on the same task is not allowed; " \
          "use Transaction#savepoint for nested atomicity"
  end

  @pinned_gate.acquire do
    raise @pinned_error if @pinned_error
    raise ShutdownError, "pool is closing" if @closing

    owner = Async::Task.current
    conn = nil
    @pinned_active += 1
    @pinned_owners[owner] += 1

    begin
      conn = @pinned_free.pop || PoolOps.new_connection(@connection_args)
      raise @pinned_error if @pinned_error
      raise ShutdownError, "pool is closing" if @closing

      @pinned_in_use[conn] = owner
      yield conn
    ensure
      @pinned_in_use.delete(conn) if conn
      release_pinned(owner, conn)
    end
  end
end